docs: def rebase(self):
          """
          Change the backing-file entry of the exported disk.
          Please refer to 'qemu-img rebase' manual for more info.
          """
          if self.standalone:
              rebase_msg = 'Merging layered image with base'
          else:
              rebase_msg = 'Rebase'
  
          with LogTask(rebase_msg):
              if len(self.src_qemu_info) == 1:
                  # Base image (doesn't have predecessors)
                  return
  
              if self.standalone:
                  # Consolidate the layers and base image
                  utils.qemu_rebase(target=self.dst, backing_file="")
              else:
                  if len(self.src_qemu_info) > 2:
                      raise utils.LagoUserException(
                          'Layered export is currently supported for one '
                          'layer only.  You can try to use Standalone export.'
                      )
                  # Put an identifier in the metadata of the copied layer,
                  # this identifier will be used later by Lago in order
                  # to resolve and download the base image
                  parent = self.src_qemu_info[0]['backing-filename']
  
                  # Hack for working with lago images naming convention
                  # For example: /var/lib/lago/store/phx_repo:el7.3-base:v1
                  # Extract only the image name and the version
                  # (in the example el7.3-base:v1)
                  parent = os.path.basename(parent)
                  try:
                      parent = parent.split(':', 1)[1]
                  except IndexError:
                      pass
  
                  parent = './{}'.format(parent)
                  utils.qemu_rebase(
                      target=self.dst, backing_file=parent, safe=False
                  )